1. Field of the Invention
The present invention relates to dispensing cabinets for sheet material and, more particularly, to a dispensing cabinet which sequentially dispenses sheet material from a primary roll and a reserve roll held within the cabinet. The invention is particularly useful for dispensing paper towels.
2. Brief Description of the Prior Art
In the past, dispensing cabinets have been designed to dispense two rolls of sheet material, such as paper towels, sequentially so that upon the depletion of sheet material from one of the rolls, the unwinding of the second roll was commenced. The past dispensing cabinets have typically included a pair of feed rollers through which the sheet material is passed. The feed rollers are attached to crank arms, either directly or through a gearing arrangement, which are used to crank out the portion of sheet material to be used. Initially, sheet material from the primary roll was placed through the nip of the feed rollers and upon depletion of the primary roll, the leading end of the sheet material from the reserve roll was transferred into the nip formed by the feed rollers.
The dispensing mechanisms of typical prior art dispensing cabinets have not been completely reliable, especially where unwinding of the second roll was to be commenced. This often caused problems since the failure of the second roll to unwind resulted in unavailability of sheet material until the dispensing cabinet received service, which of course, frustrates the very purpose of a two-roll cabinet since the rolls are sequentially dispensed to allow greater time intervals between servicing.
Examples of prior art cabinets in which the leading end of the reserve roll is transferred into the feed rollers upon depletion of the primary roll are described in U.S. Pat. Nos. 2,930,664 to Liebisch; 3,007,650 to Burton; 3,126,234 to Batlas et al; 3,288,387 to Craven, Jr.; and 3,628,743 to Bastian. The dispenser disclosed in U.S. Pat. No. 3,628,743 to Bastian has been proven to be particularly satisfactory for certain uses. It includes a rotatably mounted transfer roller which is movable against one of the feed rollers, the one which is driven, in response to substantial depletion of the sheet material on the primary roll. The leading end of the sheet material from the reserve roll is positioned between the transfer roller and the feed roller while the primary roll is being used, but upon movement of the transfer roller towards the feed rollers the sheet material from the reserve roll is pressed against the driven roller. The driven feed roller, upon being turned by an attached crank handle, then advances the reserve roll sheet material towards the feed roller nip. At the same time, a prong holding the end of the reserve roll sheet material prevents advancement of the sheet material past the feed rollers and thereby forces it to crowd into the feed roller nip.
The principle shortcoming of the dispensing cabinet described in U.S. Pat. No. 3,628,743 is that it requires the driven feed roller, with which the transfer roller engages, to be on the reserve roll side of the feed roller nip. Other cabinet design considerations in combination with the requirement to employ crank handles which turn in the conventional direction places restrictions upon the driving arrangements which can be provided between the crank handle and the feed rollers. For example, the above-described cabinet has been restricted generally to use with reversing gears to cause the driven feed roller to turn in the direction opposite to that of the crank handle. While it is possible to reverse the position of the driven feed roller so that it is on the side of the nip opposite the position of the reserve roll, there will then be a tendency to crank the leading end of the reserve roll sheet material past the feed roller nip and transfer roller without the required crowding to force the sheet material into the nip because there will not be the blocking action provided by the prong.
Accordingly, it is a principal object and advantage of the present invention to provide a new and improved dispensing cabinet for sequentially dispensing sheet material from first and second rolls of spirally wound sheet material in a reliable manner.
It is a still further object and advantage of the present invention to provide an improved mechanism in a dispensing cabinet for automatically commencing the feeding of sheet material from a second roll upon depletion of sheet material from a first roll in a manner which permits either feed roller to be driven.